Troubleshooting Reverse and Brake Lights

Question:

We have a 1975 dodge coachman sportsmen and hooked up lights and we cant get brack or back up lights

asked by: Ann

Expert Reply:

It sounds like you are having trouble with the signals on the trailer connector on your 1975 Dodge van conversion RV. The type of trailer socket that carries reverse light signals is the 7-way type, like # 37185, which is included in our 7-way installation kit # ETBC7.

You can disconnect the trailer and test the vehicle socket directly using a circuit tester like # PTW2993. The linked video shows how to use the tester to check for the correct signals on the 7-way. You'll need an adult helper to press the emergency brake and hold the foot brake while shifting the van into reverse; this will allow you to test to see if the reverse light signal is making it to the socket. It should be on the center pin. The brake lights should appear on the contacts at both the 3- and 9-o-clock positions when your help presses the brake pedal.

If you do not detect these signals check your wiring harness main ground wire to ensure it is tightly attached to a clean bare metal spot on the vehicle. A weak ground can cause some lighting functions to not work. Another likely cause is corrosion on or inside the trailer connectors. If your 7-way is corroded you will want to replace it. You can send me a photo of the trailer socket and I can then help you select a replacement.

expert reply by: Adam R